Transcriptome analysis of salt stress response in halophyte Atriplex centralasiatica leaves

As a typical halophyte living in saline environments, Atriplex centralasiatica sequesters excess salt away via metabolically active epidermal bladder cells to prevent salt damage. In the present study, we aimed to screen genes involved in salt excretion, osmotic adjustment and transcriptional regulation in A. centralasiatica leaves by high-throughput RNA sequencing. A. centralasiatica were treated with 300 mM NaCl for 7 days. We found that the volume of bulliform cells of salt bladders was significantly increased, and Na/Cl were accumulated on the surface of salt bladders. Moreover, RNA sequencing revealed that 9144 unigenes were differentially expressed, including 3819 up-regulated unigenes and 5325 down-regulated ones. The gene ontology (GO) enrichment analysis showed that several groups of genes were significantly up-regulated under NaCl salt stress, which were associated with ion transport, reactive oxygen species (ROS) scavenging, abscisic acid (ABA)-dependent signaling pathway and transcription factors. The excessive Na+ and Cl- were conveyed into the huge central vacuole by highly expressed sodium/potassium transporters (such as HKT1 and CNGC14). Several candidate genes of ABA-dependent stomatal movements (such as ABI1 and OST1), photosynthesis (such as NPQ2) and ROS (such as TAU 25) pathways were predicted to reduce salt stress-induced damage. Collectively, these above-mentioned results offered valuable insights into the mechanisms underlying the responses of recretohalophyte A. centralasiatica to salt stress.